Heat dissipation device having a rotatable fastener

ABSTRACT

A heat dissipation device includes a heat sink, a retention module and a rotatable fastener for securing the heat sink to the retention module. The retention module includes two supporting ribs and a positioning block above one of the supporting ribs. The rotatable fastener is rotatably received in the retention module and includes an actuating portion and a pressing portion fastened to the actuating portion. The heat sink rests on the supporting ribs of the retention module with an end thereof being pressed by the positioning block, and an opposite end thereof being pressed by the pressing portion. The rotatable fastener can be rotated to an unlocked position wherein the pressing portion is moved away from the opposite end of the heat sink, so that the heat sink is removable from the retention module.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to heat dissipation devices, andmore particularly to a heat dissipation device having a rotatablefastener for securing a heat sink to a heat-generating component such asa central processing unit (CPU) mounted on a printed circuit board.

2. Description of Related Art

It is widely acknowledged that heat is produced during operations ofelectronic devices such as central processing units (CPUs). The producedheat must be quickly removed to ensure the CPUs working normally.Typically, a heat sink is disposed on the CPU to dissipate the heattherefrom.

In earlier times, linear-type locking devices were widely used forsecuring of heat sinks. A linear-type locking device, which isintegrally made from a resilient metal wire, generally includes anelongated central pressing portion and a pair of locking arms extendingfrom opposite ends of the elongated central pressing portion in oppositedirections to thereby form a Z-shaped configuration. When assembled, theelongated central pressing portion of the linear-type locking devicelodges in a heat sink, and the locking arms thereof are then resilientlydeflected downwardly to engage with positioning means provided on aframe or socket to thereby secure the heat sink to a CPU. An example ofa linear-type locking device is shown in U.S. Pat. No. 5,386,338.However, a linear-type locking device generally has a slim structure; itcannot firmly secure a heat sink to a CPU, especially nowadays the heatsink being made bigger and heavier aiming to obtain a high heatdissipating capacity. The linear-type locking device cannot securelyfasten such a large and heavy heat sink to the CPU when the heat sink issubject to a vibration.

Thus, an improved locking device which overcomes above-mentionedproblems is required.

SUMMARY OF THE INVENTION

A heat dissipation device in accordance with a preferred embodiment ofthe present invention includes a heat sink, a retention module and arotatable fastener for firmly positioning the heat sink in the retentionmodule. The heat sink includes a base for contacting with aheat-generating component. The retention module includes a bottom walland a positioning block formed at one side thereof. The rotatablefastener is rotatably connected to the retention module and includes apressing portion for pressing the base of the heat sink towards thebottom wall of the retention module. The heat sink rests on the bottomwall of the retention module with an end thereof being pressed by thepositioning block, and an opposite end thereof being pressed by thepressing portion when the rotatable fastener is rotated in the retentionmodule to a locked position. The rotatable fastener can be at anunlocked position where the rotatable fastener is rotated relative tothe retention module to a position wherein the pressing portion is movedaway from the opposite end of the heat sink and located between twopivot tabs of the retention module. At the unlocked position, the heatsink is removable from the retention module. A spring is attached to abottom face of the pressing portion. The spring resiliently anddownwardly presses the opposite end of the heat sink when the rotatablefastener is rotated to the locked position.

Other advantages and novel features will become more apparent from thefollowing detailed description of preferred embodiments when taken inconjunction with the accompanying drawings, in which:

BRIEF DESCRIPTION OF THE DRAWINGS

Many aspects of the present embodiments can be better understood withreference to the following drawings. The components in the drawings arenot necessarily drawn to scale, the emphasis instead being placed uponclearly illustrating the principles of the present embodiments.Moreover, in the drawings, like reference numerals designatecorresponding parts throughout the several views.

FIG. 1 is an exploded, isometric view of a heat dissipation deviceaccording to a preferred embodiment of the present invention;

FIG. 2 is a view similar to FIG. 1, but from a different aspect and witha rotatable fastener assembled to a retention module of the heatdissipation device of FIG. 1;

FIG. 3 is an assembled view of FIG. 1 with the rotatable fastener at anunlocked position;

FIG. 4 is a cross-sectional view of the heat dissipation device takenalong line IV-IV of FIG. 3;

FIG. 5 is an assembled view of FIG. 1 with the rotatable fastener at alocked position; and

FIG. 6 is a cross-sectional view of the heat dissipation device takenalong line VI-VI of FIG. 5.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 illustrates a heat dissipation device in accordance with apreferred embodiment of the present invention, which comprises a heatsink 10, a retention module 20 and a rotatable fastener 30 for securingthe heat sink 10 to a heat-generating component such as a CPU (notshown).

The heat sink 10 comprises a base 12 and a plurality of heat-dissipatingfins 14 integrally formed from a top surface (not labeled) of the base12. The heat-dissipating fins 14 extend vertically and upwardly from thetop surface of the base 12. The heat-dissipating fins 14 may be in anyconfiguration known in the art, providing that they can effectivelydissipate the heat produced by the CPU. The base 12 has two borderportions 120 at two opposite sides thereof respectively. There is no finon the border portions 120 when the fins 14 are formed on the base 12. Aprotruding portion 122 extends downwards from a center of a bottomsurface (not labeled) of the base 12, for contacting the CPU.

The retention module 20 is a substantially rectangular frame, which islocated around the CPU, and has a first sidewall 23, a second sidewall24, a third sidewall 25 and a fourth sidewall 26 cooperatively forming acircumference of the retention module 20, with an opening 220 in acenter thereof for receiving the CPU. The first and second sidewalls 23,24 are arranged opposite to the third and fourth sidewalls 25, 26,respectively. The first and third sidewalls 23, 25 each have a lengthshorter than that of each of the second and fourth sidewalls 24, 26. Apair of supporting ribs 28 are located at inner surfaces of the firstand third sidewalls 23, 25 respectively and at a location adjacent to abottom side of the retention module 20. The first sidewall 23 forms twoadjacent and horizontal pivot tabs 230 at a middle portion thereof, forreceiving the rotatable fastener 30 therein. The pivot tabs 230 extendoutwardly and horizontally from an outer surface of the first sidewall23 and each have an arc-shaped configuration. Each pivot tab 230 definesa pivot hole 232 in a center thereof for receiving the rotatablefastener 30 in the retention module 20. An elongate mouth 234 is definedin a projecting portion at an inner surface of the first sidewall 23.The elongate mouth 234 is defined above the supporting rib 28 of thefirst sidewall 23 and between the two pivot tabs 230, for a pressingportion 32 of the rotatable fastener 30 to extend therethrough when therotatable fastener 30 is rotated to a locked position. A positioningblock 250 is horizontally located at an inner surface of the thirdsidewall 25 and above the supporting rib 28 of the third sidewall 25,for pressing downwards a corresponding border portion 120 of the base 12of the heat sink 10.

The rotatable fastener 30 is rotatably assembled to the retention module20 and used to press the base 12 of the heat sink 10 towards theretention module 20 and the CPU. The rotatable fastener 30 comprises thepressing portion 32, an actuating portion 34 vertically extendingthrough the pressing portion 32 and a bolt 36 horizontally extending inthe pressing portion 32 and the actuating portion 34 to fasten thepressing portion 32 to the actuating portion 34. The pressing portion 32generally has a fan-like shape and has a spring 320 mounted on a bottomsurface of the pressing portion 32, for tightly pressing correspondingone of the border portions 120 of the heat sink 10 towards thesupporting tab 28 of the first sidewall 23 of the retention module 20. Aretaining hole 322 is defined in a center of a circular base (notlabeled) of the pressing portion 32, for receiving a middle part of theactuating portion 34 therein. A bore 324 is laterally defined in a wallof the base of the pressing portion 32, for the bolt 36 to extendtherethrough to enter the retaining hole 322. The actuating portion 34has a round column-like body (not labeled) and a handle 340 formed at anupper end thereof. A through hole 342 is transversely defined in amiddle portion of the body of the actuating portion 34, for the bolt 36to extend therein. The bolt 36 has a body 360 and a head 362 located atone end of the body 360. The body 360 is used to insert in the bore 324of the pressing portion 32 and the through hole 342 of the actuatingportion 34 until the head 362 abuts against the actuating portion 34,whereby the actuating portion 34 and the pressing portion 32 aresecurely connected together.

In assembly of the rotatable fastener 30 to the retention module 20,firstly the pressing portion 32 is placed between the two pivot tabs 230with the retaining hole 322 of the pressing portion 32 in line with thepivot holes 232 of the two pivot tabs 230. The actuating portion 34 isthen brought to extend downwardly through the retaining hole 322 of thepressing portion 32 and the pivot holes 232 of the two pivot tabs 230,until the through hole 342 of the actuating portion 34 faces the mouth234 of the first sidewall 23 of the retention module 20. Then, the bolt36 is brought to extend through the mouth 234 of the first sidewall 23,the bore 324 of the pressing portion 32 and the through holes 342 of theactuating portion 34 and is inserted in the pressing portion 32 and theactuating portion 34 with the head 362 of the bolt 36 tightly abuttingagainst the pressing portion 32, whereby the actuating portion 34 andthe pressing portion 32 are fastened together in the retention module 20by the bolt 36. The pressing portion 32 is rotatably located between thetwo pivot tabs 230 of the retention module 20. The actuating portion 34is received in the pivot holes 232 of the two pivot tabs 230. A rotationof the actuation portion 34 by manipulating the handle 340 causes thepressing portion 32 to rotate accordingly.

In assembly, referring to FIGS. 3-4, firstly one of the border portions120 of the base 12 of the heat sink 10 is inserted between thepositioning block 250 and the supporting rib 28 of the third sidewall 25of the retention module 20, wherein the positioning block 250 exerts adownward pressing force on the border portion 120 of the base 12 torender the border portion 120 tightly abut against the supporting rib 28of the third sidewall 25 of the retention module 20. At this stage, therotatable fastener 30 is at an unlocked position. The pressing portion32 of the rotatable fastener 30 is placed between the two pivot tabs 230and the spring 320 abuts a top surface of a lower one of the pivot tabs230 (shown in FIG. 4). Referring to FIGS. 5-6, by rotating the actuatingportion 34 of the rotatable fastener 30 by operating the handle 340, thepressing portion 32 is moved to pass through the mouth 234 of the firstsidewall 23 and press downwards the other border portion 120 of the base12 towards the supporting rib 28 of the first sidewall 23 of theretention module 20. At this position, the spring 320 is brought todownwardly press the other border 120 of the base 12 of the heat sink 10towards the supporting rib 28 of the first sidewall 23 of the retentionmodule 20. The other border portion 120 of the base 12 is thus tightlysandwiched between the pressing portion 32 and the supporting rib 28 ofthe first sidewall 23 due to action of spring force produced by thespring 320 of the pressing portion 32, whereby the other border portion120 is urged toward the supporting rib 28 of the first sidewall 23 ofthe retention module 20. Therefore, two opposite end portions of thebase 12 of the heat sink 10 are pressed by the positioning block 250 andthe pressing portion 32 of the rotatable fastener 30 to tightly abutagainst the supporting ribs 28 of the retention module 20, whereby theheat sink 10 is securely retained in the retention module 20.

According to the above embodiment of the present invention, thepositioning block 250 of the retention module 20 and the pressingportion 32 of the rotatable fastener 30 have a large contacting surfacewith the two end portions of the base 12 of the heat sink 10. Therefore,the heat sink 10 is more firmly secured in the retention module 20 viathe positioning block 250 and the pressing portion 32 pressing on thebase 12 of the heat sink 10, in comparison with a linear-type lockingdevice generally with a slender structure. The rotatable fastener 30 isrotatably connected to the retention module 20, such that when therotatable fastener 30 is at the unlocked position, the pressing portion32 of the rotatable fastener 30 is rotated to the position between thepivot tabs 230, whereby the heat sink 10 is removable from the retentionmodule 20. When at the locked position, the positioning block 250 andthe pressing portion 32 downwardly press the base 12 of the heat sink 10on the supporting ribs 28 of the retention module 20. So, it isexpedient to secure the heat sink 10 in the retention module 20 andattach the heat sink 10 to the CPU.

For removal of the heat sink 10 from the retention module 20, byrotating the actuating portion 34 of the rotatable fastener 30, thepressing portion 32 is moved to disengage from the other border 120 ofthe base 12 of the heat sink 10. Here, the pressing force of thepressing portion 32 acting on the other border 120 of the base 12 of theheat sink 10 is released, and the heat sink 10 is removed from theretention module 20 with the left border 120 as viewed from the drawingsbeing drawn out from the retention module 20. Thus, the disassembly ofthe heat sink 10 from the retention module 20 is also expedient.

It is believed that the present embodiments and their advantages will beunderstood from the foregoing description, and it will be apparent thatvarious changes may be made thereto without departing from the spiritand scope of the invention or sacrificing all of its materialadvantages, the examples hereinbefore described merely being preferredor exemplary embodiments of the invention.

1. A heat dissipation device comprising: a heat sink comprising a baseadapted for contacting a heat-generating component; a retention moduleadapted for being located around the heat-generating component, theretention module comprising a pair of supporting portions at twoopposite sidewalls thereof and a positioning block being positionedabove one of the supporting portions; and a rotatable fastener rotatablyconnected to the retention module at a position opposite the positioningblock and having a pressing portion being movable relative to theretention module between unlocked and locked positions; wherein at thelocked position the base of the heat sink rests on the supportingportions of the retention module with an end portion of the heat sinkbeing pressed by the positioning block and an opposite end portion ofthe heat sink being pressed by the pressing portion of the rotatablefastener, and at the unlocked position, the rotatable fastener isrotated to a position wherein the pressing portion is moved away fromthe opposite end portion of the heat sink.
 2. The heat dissipationdevice as claimed in claim 1, wherein the rotatable fastener comprisesan actuating portion extending in the pressing portion and securelyconnected therewith and the retention module forms at least one pivottab with at least one pivot hole defined therein, and wherein theactuating portion is rotatably received in the at least one pivot hole.3. The heat dissipation device as claimed in claim 2, wherein therotatable fastener comprises a bolt inserted in the pressing portion andthe actuating portion to fasten the pressing portion to the actuatingportion.
 4. The heat dissipation device as claimed in claim 3, whereinthe retention module comprises a pair of pivot tabs extending outwardlyand the pressing portion of the rotatable fastener is located betweenthe two pivot tabs when the pressing portion is moved to the unlockedposition.
 5. The heat dissipation device as claimed in claim 4, whereinthe retention module defines a mouth opposite the positioning block, thepressing portion of the rotatable fastener passing through the mouth topress on the base of the heat sink when the rotatable fastener is movedfrom the unlocked position to the locked position.
 6. The heatdissipation device as claimed in claim 5, wherein the pressing portionof the rotatable fastener comprises a spring exerting a downwardlypressing force on the base of the heat sink when the pressing portion isat the locked position.
 7. The heat dissipation device as claimed inclaim 5, wherein the actuating portion of the rotatable fastener has ahandle at an upper end portion thereof, for facilitating exertion of arotation force to the rotatable fastener.
 8. The heat dissipation deviceas claimed in claim 1, wherein the base of the heat sink has two borderportions at two opposite sides thereof respectively, one border portionbeing sandwiched between the positioning block and one of the supportingportions of the retention module, and the other border portion beingpressed by the pressing portion of the rotatable fastener to abutagainst the other supporting portion of the retention module when therotatable fastener is at the locked position.
 9. The heat dissipationdevice as claimed in claim 8, wherein the base of the heat sinkcomprises a protruding portion extending downwardly from a bottomthereof, adapted for contacting the heat-generating component.
 10. Aheat dissipation device adapted for dissipating heat generated by anelectronic device mounted on a printed circuit board, comprising: aretention module adapted for mounting on the printed circuit board andsurrounding the electronic device, the retention module comprising apositioning block disposed at one side thereof; a heat sink adapted forcontacting with the electronic device, being mounted on the retentionmodule and having a portion pressed by the positioning block to abutagainst a bottom wall of the retention module; and a rotatable fastenerhaving an actuating portion rotatably received in the retention moduleand a pressing portion fastened to the actuating portion and exerting apressing force on an opposite portion of the heat sink towards thebottom wall of the retention module when the rotatable fastener isrotated from an unlocked position to a locked position.
 11. The heatdissipation device as claimed in claim 10, wherein the retention modulecomprises a pair of pivot tabs extending outwardly from a side edge ofthereof, the actuating portion being rotatably extended in the pivottabs and the pressing portion being located between the two pivot tabswhen the rotatable fastener is at the unlocked position.
 12. The heatdissipation device as claimed in claim 1, wherein the rotatable fastenercomprises a bolt extending in the pressing portion and the actuatingportion to fasten the pressing portion and the actuating portiontogether.
 13. The heat dissipation device as claimed in claim 12,wherein the retention module defines a mouth in a sidewall thereofcorresponding to the pressing portion of the rotatable fastener, themouth being provided for the pressing portion to extend therethroughwhen the rotator is moved from the unlocked position to the lockedposition.
 14. The heat dissipation device as claimed in claim 12,wherein the pressing portion defines a retaining hole therein and theactuating portion is received in the retaining hole.